This application relates to apparatus for controlling the liquid level in vessels and, in particular, to such apparatus for use in toilet flush tanks. The apparatus disclosed herein is an improvement of that disclosed in U.S. Pat. No. 6,123,099.
The aforementioned patent discloses several types of valves utilizing a flexible, resilient pinch tube as the valve member, which is controlled by an actuator engageable with the outside of the tube to pinch it closed. The embodiment disclosed in FIGS. 12-17 of that patent utilizes a float which encircles and rides up and down along an upright fill tube so as to occupy less lateral. space in the tank. A rib on the float engages a similar rib on the fill tube to temporarily arrest the upward movement of the float. The arresting mechanism resiliently yields when the buoyancy force of the rising water level on the float reaches a sufficient value, for suddenly closing the valve to provide a snap-action shutoff. The shutoff water level, however, is not adjustable.
Furthermore, prior valve mechanisms utilizing pinch tube valves are designed to operate over a relatively narrow range of water pressures and may not completely close at higher water pressures.
This application discloses a flush valve assembly which avoids the disadvantages of prior valve assemblies while affording additional structural and operating advantages.
An important aspect is the provision of a flush valve assembly which provides a snap-action valve shutoff while, at the same type, affording easy manual adjustment of the shutoff water level.
Another aspect is the provision of a flush valve assembly which is operable over a wide range of water pressures, including very high water pressures.
Still another aspect is the provision of a flush valve assembly of the type set forth, which utilizes water pressure to assist valve closure.
Yet another aspect is the provision of a unique method of flush valve assembly operation.
Certain ones of these and other aspects may be attained by providing a flush valve assembly for controlling flow of liquid from a pressurized source to a vessel comprising: a conduit coupled between the source and the vessel and having a closeable portion, a closing mechanism shiftable between an opening condition and a closing condition cooperating with the closeable portion for closing it, the closing mechanism including a cylinder having a control port therein and coupled to the source and a piston disposed in the cylinder, and a liquid level-responsive mechanism for closing the control port so that source pressure in the cylinder drives the piston toward the closing condition of the closing mechanism.
Still other aspects may be attained by providing a flush valve assembly of the type set forth, wherein the liquid level-responsive mechanism includes a float coupled to the closing mechanism and disposed in the liquid in the vessel for movement in response to changes in the liquid level in the vessel, and further comprising a control mechanism including a first arresting portion carried by the float and a second arresting portion cooperatively associated with the float, one of the first and second arresting portions including a manually adjustable portion for selectively varying degree of interference between the first and second arresting portions, the control mechanism being responsive to rising of the float to a predetermined stop level below a highest level for moving to a stop condition with the first arresting portion engaging the second arresting portion for mechanically arresting further upward movement of the float, the control mechanism, when in the stop condition, being responsive to a predetermined buoyancy force exerted on the arrested float when the liquid has risen substantially to the highest level for shifting to a release condition by disengagement of the first arresting portion from the second arresting portion for releasing the float and permitting the float to move suddenly to the highest level to actuate the closing mechanism to its closing condition.